1. Field of the Invention
This invention generally relates to methods for making modified asphalt materials.
2. Description of the Related Art
Conventional air-blowing of asphalt materials involves passing an oxidizing gas through the asphalt in a molten condition. In general, the effect of such conventional air-blowing is to partially oxidize the asphalt, resulting in decreased penetration and increased viscosity and softening point. However, for paving applications, such conventional air-blowing generally has a negative effect on the fatigue resistance and the low temperature properties.
The disclosures of the following references are hereby incorporated by reference in their entireties: U.S. Pat. Nos. 1,782,186; 2,179,208; 2,370,007; 2,450,756; 3,126,329; 3,462,359; 4,338,137; 4,440,579; 4,456,523; 4,456,524; 5,284,509; 5,336,705; 5,342,866; and 6,087,419. The following EPO patent documents are also hereby incorporated by reference in their entireties: EP 0 459 811 B1 and EP 0 618 274 A1.